Extensive use of fossil fuels and consequential high levels of carbon dioxide (CO2
) emissions are major contemporary challenges.1
The most direct way to mitigate this process is to activate the reverse chemical pathways in which CO2
is reduced into high-energy molecules.2
The electrochemical reduction of CO2
to CO has attracted increasing attention, since CO represents a valuable intermediate to the production of synthetic fuels using established processes, such as Fischer-Tropsch.3-6
One approach to electrochemically reduce CO2
to CO is using solid oxide electrolysis cells (SOECs). SOECs are solid-state electrochemical systems that, in principle, can facilitate the electrochemical reduction of CO2
to CO with potentially very high rates due to the favorable kinetics at high operating temperatures.7
While electrochemical reduction of CO2
using SOECs offers a great deal of promise, these systems are limited by the inability to operate near the thermodynamic reversible potentials due to the activation overpotential losses.1
In the present work, we combine experimental and theoretical techniques to determine the factors that lower the overpotential losses in SOECs during electrolysis of CO2
. We find that the conventional Ni-yttria stabilized zirconia (Ni-YSZ) composite cathodes exhibit significant overpotential losses toward electrochemical reduction of CO2
. Incorporation of gadolinium-doped ceria (GDC) improves the SOEC performance. We have conducted controlled electrochemical studies to investigate the influence of gadolinium-doped ceria in the electrochemical reduction of CO2.
1. S.D. Ebbesen, S.H. Jensen, A. Hauch, M.B. Mogensen, Chem. Rev. 114 (2014) 10697-10734.
2. B.P. Sullivan, K. Krist, H. Guard, Elsevier, 2012.
3. C. Sanchez-Sanchez, V. Montiel, D. Tryk, A. Aldaz, A. Fujishima, Pure Appl. Chem. 73 (2001) 1917-1927.
4. K. Xie, Y. Zhang, G. Meng, J.T. Irvine, Energy Environ. Sci. 4 (2011) 2218-2222.
5. E. Iglesia, Appl. Catal., A. 161 (1997) 59-78.
6. D. Wilhelm, D. Simbeck, A. Karp, R. Dickenson, Fuel Process. Technol. 71 (2001) 139-148.
7. C. Graves, S.D. Ebbesen, M. Mogensen, Solid State Ionics, 192 (2011) 398-403.